The Norwegian stock market briefly suffered a drop of as much as 4% on Monday in the latest so-called flash crash to hit exchanges.
The drop from in the Oslo Bors All Shares index
was unexplained and not met by similar declines across Europe. The index moved back in line with other markets in about ten minutes.
Trading conditions were on the thin side with London closed for a bank holiday.
Markets globally have suffered on worries about rising interest rates.